1. Field of the Invention
This invention relates to a numerical control machining system, and more particularly to a system which is capable of freely performing transfer of processing programs between a plurality of numerical control machines (hereinafter also called "NC machine") interconnected via a communication interface.
2. Description of the Related Art
Heretofore, numerical control machines have been practiced in a wide variety of processings. In general, these NC machines take their respective processing works independently of one another, and for this reason, processing programs are supplied to the respectively NC machines individually.
Recently, attempts have been made to provide a unified system in an effort to share many programs between a plurality of NC machines. In such conventional combined numerical control machining system, the NC machines are unified by a factory automation computer (hereinafter called "FA computer"), and many processing programs are stored in the FA computer in a centralized fashion, so that the individual processing program can be transmitted from one NC machine to another NC machine when necessary.
FIG. 5 of the accompanying drawings schematically shows a typical conventional numerical control machine NC which includes a processing program storage means 5. In FIG. 5, using a key input means 1 such as in the form of a keyboard, the operator inputs key data to operate the NC machine NC. A display means 2 such as in the form of a CRT unit displays a program, the order of processing procedures, a state of diagnosis, etc. of the NC machine NC to notify the operator of them.
A key data interpreting means 3 connected to the keyboard I is included in a CPU with a control program for the NC machine NC and interprets the key data from the keyboard 1 to give a command meeting the key data. A display data preparing means 4 converts information in the NC machine NC into such data as to be displayable on the display means 2. The display data preparing means 4, like the key data interpreting means 3, is included in the CPU of the NC machine NC.
The processing program storage means 5 is in the form of an IC memory, a disk unit, a bubble memory or the like, each of which is capable of storing a plurality of processing programs. A communication interface 6 such as in the form of an RS232c port is associated with the NC machine NC for communication with external equipment.
A down-load answering means 8 gives an answer to a down-load request given from the external equipment via the communication interface 6, and as a result, the down-load answering means 8 receives a processing program transmitted from the external equipment and stores the processing program. The down-load answering means 8 also is included in the CPU.
An up-load answering means 10 gives an answer to an up-load request given from the external equipment via the communication interface 6, and as a result, the up-load answering means 10 reads a processing program from the processing program storage means 5 and transmits the processing program to the external equipment via the communication interface 6. This upload answering means 10 also is included in the CPU.
FIG. 6 shows an example in which a plurality of conventional NC machines are combined to provide a network for transfer of processing programs between the NC machines. In FIG. 6, an FA computer FAC stores a large number of processing programs and takes a down-load or an up-load of a processing program for the individual NC machine to which the FA computer FAC is connected. The FA computer FAC, like the NC machine NC of FIG. 5, is equipped with a communication interface 26 for communication with the other NC machines NC.sub.1, NC.sub.2 . . . , and a processing program storage means 25 for storing processing programs. Also, a keyboard 21 and a key data interpreting means 23 are located in the FA computer FAC.
A down-load requesting means 27 issues a request to down-load a processing program with respect to the NC machine NC via the communication interface 26 and confirms an answer from the NC machine NC, whereupon the down-load requesting means 27 reads a predetermined processing program from the processing program storage means 25 to transmits the processing program to the NC machine NC via the communication interface 26. The down-load requesting means 27 is included, for example, in a CPU which is controlled by a control program is included in an FA computer FAC.
An up-load requesting means 29 issues a request to up-load a processing program with respect to the NC machine NC via the communication interface 26 and confirms an answer from the NC machine NC, whereupon the up-load requesting means 29 scoops up a predetermined processing program from the NC machine NC via the communication interface 26 to store in the processing program storage means 25. This up-load requesting means 29 also is included in the CPU of the FA computer FAC.
The operation of this conventional processing system will now be described. Heretofore, it has been a common practice to control a large number of processing programs in a centralized fashion at the FA computer FAC so that a processing program is transmitted to the NC machine NC upon necessity. Advantageous features of this system are that many processing programs can be collected at a single place and hence can be put in order without difficulty, and that each NC machine NC is only required to have a processing program storage place necessary to at most one processing.
To down-load a certain processing program to the NC machine NC, the operator operates the key input means 21 of the FA computer FAC to give a command to the down-load requesting means 27, whereupon the download requesting means 27 reads a desired processing program from the processing program storage means 25 to transmit the processing program to a predetermined NC machine NC via the communication interface 26. In response to this transmission, a down-load answering means 8 of the NC machine NC is made operative to receive the processing program via the communication interface 26 of the NC machine NC and then to store the processing program in the processing program storage means 5 of the NC machine NC.
Therefore, according to the above conventional system, the processing program storage means 5 of each NC machine NC requires only a small memory capacity. As the FA computer FAC possesses a large number of processing programs, it is possible to cause many NC machines NC, connected to this FA computer FAC, to take a variety of processing actions.
Although each NC machine NC includes a control part for reading a processing program and outputting the same program to a practical processing machine, its description is omitted here for clarity.
The unification of the processing programs by combining the NC machines and the FA computer is also known from Japanese Patent Laid-Open Publication No. 44808/1987, though there can be found something different.
In this conventional system, a group of NC processing machines are centralized at a communication node mounted in a central control unit, which must be mounted in a certain part other than the NC machines. Further, since the processing programs are stored and adminstrated in a centralized fashion so that a processing program is transmitted to the NC machines upon necessity an FA computer is necessary for the centralized control, thus causing an increased cost of production.